Nice improvement, for sure.
Did the factory make a special effort to sharpen the front-bottom-left corner of that Mepro-21, or were you just lucky enough to get one that missed the de-burring step? That looks absolutely wicked, in relation to the charging handle path. I would have needed an EMT to shadow me if I was slapping that gun around at high speed. Hell, the exposed ends of the mounting base screws and nuts would have been enough to send me to the ER a couple of times a month...
"Placement is power" -- seen in an article by Stephen A. Camp
(RIP, Mr. Camp; you will be remembered, and missed)